title: Mechanism of edge restenosis after drug-eluting stent implantation. Angulation at the edge and mechanical properties of the stent.
abstract: BACKGROUND
  Edge restenosis is not an unusual finding after implantation of drug-eluting stents (DES). We hypothesized that mechanical stress imposed on the stent edge would cause vessel wall injury and inflammation, which may consequently lead to edge restenosis.
  
  
  RESULTS
  In total, 1,496 patients were implanted with a sirolimus-eluting stent (SES), paclitaxel-eluting stent (PES) or zotarolimus-eluting stent (ZES) in Seoul National University Hospital between 2007 and 2009. Binary restenosis occurred in 161 lesions in 119 patients. We retrospectively compared the 3 DES with regard to the percentage of edge stent restenosis among all cases of restenosis. We also evaluated the maximal, minimal, and Δ (maximal angle-minimal angle) angles. The percentage of edge restenosis was higher for SES than for ZES (37.5% vs. 16.7%, P=0.017). Maximal angle at the proximal edge was 64.82°±33.46° for 26 stents with proximal edge restenosis compared with 31.84°±31.51° for 89 stents without proximal edge restenosis (P=0.001). The Δ angle was also significantly different between the 2 groups (14.81°±15.98° vs. 7.60°±8.86°, P=0.035). Similar findings were observed for distal edge restenosis. Both the maximal angle (39.09°±21.04° vs. 22.71°±22.83°, P=0.010) and Δ angle (20.23°±15.39° vs. 9.18°±9.66°, P=0.016) at the distal edge were significantly different between the 2 groups.
  
  
  CONCLUSIONS
  Physical stress determined by angulation at the stent edge segment and biomechanical properties of the DES can be considered as one of the plausible mechanisms for edge stent restenosis.
authors.affiliation: Cardiovascular Center, Seoul National University Hospital.
authors.forename: Yun Gi
authors.initials: YG
authors.lastname: Kim
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Oh
authors.forename: Yoo-Wook
authors.initials: YW
authors.lastname: Kwon
authors.forename: Jung-Kyu
authors.initials: JK
authors.lastname: Han
authors.forename: Han-Mo
authors.initials: HM
authors.lastname: Yang
authors.forename: Kyung-Woo
authors.initials: KW
authors.lastname: Park
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Hyun-Jae
authors.initials: HJ
authors.lastname: Kang
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
authors.forename: Hyo-Soo
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000368:Aged; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged